Conformational flexibility of the disaccharide alpha-D-Manp-(1 -> 3)-beta-D-Glcp-OMe employing molecular dynamics simulations and trans-glycosidic (3)J(C,H) from NMR experiment

Molecular dynamics simulations of the disaccharide alphaw-D-Manp-(1-->3)-be ta -D-Glcp-OMe have been performed in vacuo and in water solution. Heteronu clear scalar coupling constants were measured across the glycosidic linkage . In conjunction with previously obtained experimental data, namely a trans -glycosidic proton-proton distance and the generalized order parameter a de scription of the molecular system is presented. The disaccharide exists in a major conformational state and has limited flexibility on a shorter time scale, i.e., less than its rotational correlation time (tau (M)). Excursion s to other conformational states are required to obtain agreement between s imulation and experiment. Thus, on a longer time scale (>tau (M)) these con formational states are populated to some extent. The combined approach of m olecular dynamics simulations and NMR experiments is therefore able to gene rate a consistent molecular picture.